Fuzzy approaches to quality function deployment for new product design

For new product development, quality function deployment (QFD) is a useful approach to maximize customer satisfaction. The determination of the fulfillment levels of design requirements (DRs) and parts characteristics (PCs) in phases 1 and 2 is an important issue during QFD processes for new product design. Unlike the existing literature, which mainly focuses on the DRs, this paper proposes fuzzy nonlinear programming models based on Kano's concept to determine the fulfillment levels of PCs with the aim of achieving the determined contribution levels of DRs in phase 1 for customer satisfaction. In addition, to deal with the design risk, this study incorporates failure modes and effects analysis (FMEA) into QFD processes, and treats it as the constraint factor in the models. To cope with the vague nature of product development processes, fuzzy approaches are used for both FMEA and QFD. The applicability of the proposed models in practice is demonstrated with a numerical example.